Problem: Simplify the following expression: ${-2(3k+9)-(7-2k)}$
Distribute the ${-2}$ into the first set of parentheses: $ {-2(}\gray{3k+9}{)} - (7-2k) $ $ {-6k-18} - (7-2k) $ The minus sign in front of the parentheses means we multiply each term inside the parentheses by ${-1}$ $ -6k-18 {-1(}\gray{7-2k}{)} $ $ -6k-18 {-7+2k} $ Rewrite the expression to group the ${k}$ terms and numeric terms: $ {-6k + 2k} {-18 - 7}$ Combine the ${k}$ terms: $ {-4k} {-18 - 7}$ Combine the numeric terms: $ {-4k} {-25}$ The simplified expression is $-4k-25$